>> Of course, the original "King James" translation did not use
italics for indicating words inserted into the text for clarity; rather
than tell you what they did, I suggest you look at a facsimile.

I have a reproduction of the 1611 KJV and it does have italics both in the
introduction and the text. The text has been modified with Roman letter but
there is no indication that italics have been added where they were not.

>>He told me that his favorite example of Biblical humor was in 1 Kings 13,
the story of the old prophet in Bethel who set off to invite the man of God
to dine with him. He said to his sons: "Saddle me the ass." So they
saddled HIM!

The 1611 have for this passage: And hee saide vnto his sonnes, Saddle me the
asse. So they sadled him the asse, and he rode thereon, x So only an oral
reading would yield the humorous point above.

>>There is a simnple solution, which translators resist mightily.
Insertions today are almost universally marked by square brackets.

Nonetheless this last point has merit and I use brackets when I translate for
a broader audience.